Ok I have a 01 330ci and I just replaced both of the cam pos sensors because that is what the codes were that i had read. Well when I did it every thing was fine for about two or three drives then when I went out to start it one day it turned over a lot more than normal but finally cranked and drove very weak and the gas milage was bad (kind of like it was out of time) but the service engine light was not on. So the next time I tried to drive it it started and drove fine for about three or four more times, then it did the same thing again so I turned it off and it started back fine and as of right now is driving fine, but I was just wondering is this going to keep happening or was the computer just resetting itself from the cps being replaced... Thanks in advance

Have you checked for fault codes? It is possible to have stored codes w/o a CEL.

I went to get the codes read but they said it would not read anything without the light on so they wouldnt even try it.

They'd be wrong. One the DME (or any other module) has detected a fault that code will be stored in non-volatile memory and will remain whether the light is on or not. There are some faults that will never turn on the CEl and others that result in just a brief flash of a CEL.

I'd suggest taking the car to a dealer or BMW indie shop and have them run a diagnostic scan. Partly because they'll have a better understanding of the car and partly because they will have BMW specific scan tool. A generic scan tool like you'd find at an auto part house or general auto shop may not produce accurate or complete results on a BMW.

+1

Your car can throw many "pending" codes which will not activate the CEL but can indicate many different problems as they are starting. P0171 is an example of a 'pending' code for a lean condition that is not dangerous to the motor...so it will not trip the CEL (as an example).

Get scanned at Autozone for free and see what is there.

It may go in limp mode when it detects an engine threatening fault even for a fraction of a second and store the code in his memory.